Infantry squads have paper for armor, that's what is implied in INFANTRY!
^Not a real argument, but whatever.
THe germans have plenty of options for wiping infantry. In fact, the germans have 3 nondoctrinal units to do so. The Brummbar has the exact same AOE value as the ISU, and it has a vet artillery strike. Then there is the Panzerwerfer, which fires 12 rockets at a single position from far range, and is usually either a wipe or heavy damage to any infantry in the area. Finally, there is the Sturmtiger, which can instawipe very large concentrations, shoot through buildings, and even cripple/ instagib vehicles. Germans have plenty of options, they just usually don't bother to use them in most games because they prefer to use Tigers.
EDIT: sorry, forgot to respond to everything: The Stuka can wipe squads with a single rocket, which is not hard to hit because it is deadly accurate.
That's really not much of an argument at all.
The Brumbar sucks against tanks, has 40 range vs ISU's 70 and you need to go T4 to unlock which almost always sets you back on the ressource war.
Panzerwerfer is not a squadwipe machine by any means, it's AoE is fairly large. It's also an artillery piece with a long cooldown, sucks against tank, and comes from T4 too.
Sturmtiger, really? Very short range, incredibly long cooldown during which its a sitting duck, it's little more than a troll unit unless your opponent really sucks and doesn't get out of the way when he sees a giant 308mm mortar pointed at him.
Zu Fuss is a pain in the ass, but you can hear it coming, it's artillery with a long CD, and it sucks against tanks.
Meanwhile, the ISU shoots every 8 seconds or so, and each shot could easily wipe an infantry squad. It has 70 range, the 2nd highest for a non artillery unit, and can spot for itself. It's very good against tank, what little it lack in penetration it makes up for in Crew shock potential. You can't get out of its way when the range can easily cover close to half the map. Shrecks will get obliterated unless your opponent is a noob that never supports his ISU. AT guns get easily decrewed/destroyed by it. The very only way to kill a decently microed ISU if you didn't have a Jagdtiger was to zerg it with heavy tanks and hope you don't it a mine or run into guards in the process.
It was a fucking broken unit that didn't give up anything to be as good as it was. It raped infantry, was very good against tanks, was long ranged, didn't need a spotter, and even had pretty decent durability. The damn thing shouldn't even have been in the game in the first place, having a unit that can easily wipe squads from more than a screen away with almost no effort is terrible design. I am definitely not sorry to see that it now requires a modicum of micro. Far as I'm concerned Relic could have removed the unit (as well as the Jagdtiger) altogether and I would only have cheered.